1: Acts or behavior displaying extreme stupidity or callousness; anything typically characteristic of a really big dink.
2: Acts or behavior that involves such injury to one's testes as to render them (temporarily or permanantly) incapable of feeling.

1: "I'm pretty sure he just swore at a cop! I haven't seen such numb-nuttedness in ages!"
2: "I went for a jog once in february...in my boxers. I've heard of numb-nuttedness, but this was ridiculous!"